This application is a Division of application Ser. No. 729,830, filed Oct. 5, 1976, now Pat. No. 4,167,941 and entitled Mechanically Operated Dispensing Device With Means For Increasing Discharge Pressure And Dispensing Time.
This invention relates to a mechanically operated dispensing device for discharging materials under pressure, and in a preferred form, relates to such devices for effecting a spray of the material.
In the prior art, many different types of dispensing devices are provided, and include aerosol spray discharge devices operated by chemical propellants and pump operated spray discharge devices. Both of these prior art types of dispensers create a hazard to the environment and recent legislation has indicated that such propellant operated devices may be prohibited in a few years due to the potential harm to the environment caused by the propellants used in such devices to effect discharge of the material. Additionally, propellant operated devices must be specially constructed in order for the containers to withstand internal pressures, and a danger to children is created due to the likelihood of a small child operating the device and effecting discharge of a potentially harmful material into the face or eyes of the child. Chemical propellant operated dispensing devices further are limited in their use due to chemical incompatibility between the propellant and the material to be discharged.
Pump type dispensing devices, while not possessing the disadvantages that chemical propellant operated dispensing devices have, nonetheless are unsatisfactory for several reasons, including the fact that they are difficult and inaccurate to use, since the pressure generated for dispensing the material is effected by operating a plunger or trigger mechanism with the finger of the user. Further, pump type devices produce only a limited spray time, since each discharge of the material is accomplished with each operation of the plunger or trigger and the like, and thus repeated operation of the pump devices is sometimes necessary in order to effect discharge of a desired amount of material. Pump devices also present a danger to small children, since they may be inadvertently operated by a child, thereby effecting discharge of a potentially harmful substance.
The present invention solves the above problems of the prior art devices, and provides a simple and rugged structure which is capable of producing a relatively long and high pressure spray with only a single operation of a spray nozzle or actuator. Moreover, very little input pressure or torque is required in order to produce a much greater discharge pressure of the material, and in fact, the pressure of the material discharged may be regulated with some forms of the invention.
Still further, the structure of the present invention is such that danger to small children and the like is reduced because of the fact that dual manipulations are required in order to effect discharge of the material, and unique leak back provisions are made, whereby the pressurized contents of the discharge device are slowing permitted to leak back into the container, thus unloading the discharge reservoir, whereby subsequent actuation of the discharge nozzle or spray by an unsuspecting person will not effect an unexpected discharge of the material.